538 Chronicles of Science. [Oct., 



to the conclusion that the phenomena of the Glacial period were 

 spread over the whole surface of the globe. 



These investigations have a direct bearing on the speculations of 

 Mr. Croll and others, the basis of whose hypotheses is the assumption 

 that the glacial phenomena were limited to extra-tropical regions. 

 Mr. Croll, indeed, has recently published a modification of his 

 original hypothesis to account for changes of climate, namely, 

 alterations in the obliquity of the ecliptic ; and has thus got into 

 another controversy with his old opponent, Mr. J. Carrick Moore. 

 The several papers which have been published on this subject will 

 be found in the numbers of the ' Philosophical Magazine ' issued 

 during the past quarter. 



The geological survey of the Grand Duchy of Hesse has recently 

 made considerable progress ; and several sheets of the map with 

 descriptive memoirs have come under our notice. Amongst them 

 we wish especially to draw attention to the map and description of 

 the Section Alzey by M. Ludwig ; and to those of the Section Mainz 

 by Herr Grooss. These maps and memoirs furnish us with the 

 most accurate descriptions yet published of two of the most classical 

 of all the German Tertiary localities, and therefore deserve more than 

 a local circulation. 



The ' Geological Magazine ' for the quarter has contained a large 

 number of original articles, but we have space to notice only two 

 or three of the most important. 



In the first place we must draw attention to a paper by Professor 

 King in the June number and an answer to it by Mr. Davidson in 

 the July number, with a notice in the latter of a paper by Mr. Meek 

 — all on the subject of the perforation or non-perforation of certain 

 Palaeozoic Brachiopoda. Dr. Carpenter has also taken part in the 

 discussion, and has published papers on the subject in the January 

 and July numbers of the ' Annals and Magazine of Natural History.' 

 The chief cause of the discussion appears to be the rather remarkable 

 fact that two forms of Spirifer (8. cuspidatus), though otherwise 

 undistinguishable, are respectively characterized by the perforation 

 of the shell in the one case, and its non-perforation in the other. 



The August number of the Magazine is chiefly remarkable for 

 containing a verbatim report of Dr. T. Sterry Hunt's lecture on the 

 chemistry of the Primeval Earth, which was delivered at the Royal 

 Institution on May 31st. 



Proceedings of the Geological Society. 



An important paper by Mr. Tate " On some Secondary Fossils 

 from South Africa," forms the commencement of the last number 

 of the Society's Journal. It contains descriptions of a large 



